Grinding mills



March 27, 1962 M. s. MlscHANsKl 3,027,103

GRINDING MILLS Filed Jan. 9, 1961 3 Sheets-Sheet 2 ATTORNEYS GRINDING MILLS 5 Sheets-Sheet 5 Filed Jan. 9, 1961 R O T N E V .N.

3,027,103 GRENDENG MELlLS Myron S. Mischanslri, 27 Englewood Road, Clifton, NJ. Filed lan. 9, 1963i, Ser. No. 81,476 7 Claims. (Cl. 24H-132) This invention relates to a grinding mill for comminuting solid material.

An object of the invention is to provide a grinding mill having pressure responsive means for varying the pressure of grinding rollers against the inner face of a grinding ring.

The invention comprehends a grinding mill having a plurality of arcuately arranged grinding rollers mounted for combined turning movement on an upright axis located centrally of the mill and with each of the grinding rollers rotatably mounted on upright axes respectively for independent rotation against the inside face of the grinding ring.

More particularly the invention resides in a grinding mill of said character in which the pressure responsive means is carried by a rotatably mounted shaft with fluid pressure means acting against said pressure responsive means for varying the grinding pressure of the rollers against the grinding ring.

Another object of the invention is to provide a grinding mill in which the grinding pressure of the rollers is produced both by fluid pressure means and by centrifugal action of the rollers and yokes rotatably carrying the rollers.

Still another object of the invention is to provide a yoke for each grinding roller having upper and lower arms between which the rollers are mounted for rotation respectively, the yoke being slidably carried by spiders affixed to the rotatably mounted shaft and with the centrifugal pressure of the rollers augmented by the pressure responsive means as desired.

With the foregoing and other objects in view, reference is now made to the following specification and accompanying drawings in which the preferred embodiments of the invention are illustrated.

In the drawings:

FIG. l is a vertical sectional view of a grinding mill constructed in accordance with the invention.

FlG. 2 is a transverse sectional view taken approximately on line 2 2 of FIG. 1.

FIG. 3 is a transverse sectional view taken approximately on line 3-3 of FIG. l.

FIG. 4 is a transverse sectional view taken approximately on line 4 4 of FIG. 5 and illustrating a modified form of the invention.

FIG. 5 is a fragmentary vertical sectional view taken approximately on line 5-5 of FIG. 4.

Referring to the drawings, the grinding mill includes a cylindrical casing consisting of upper and lower cylindrical portions l@ and l1 which are bolted or otherwise secured together. The lower portion 1i is aixed to a cylindrical base plate l2 which is secured upon spaced supporting bases 13 and f4 of concrete or other material. The lower portion l is angularly recessed on its inner face as at 1S providing a shoulder on which is supported a grinding ring i7 frequently termed a bull ring. Arranged within the housing is a central shaft 18 journaled for rotation in a thrust bearing 19 carried by a bearing support 2d which is bolted or otherwise aixed to the base plate l2. A bronze bushing 2l is mounted in the upper end of the bearing support 20 in surrounding relation with the shaft for sealing the shaft.

A plurality of radially arranged grinding rollers 22 are mounted for rotation with the shaft 18 and for independent rotation on axes disposed in parallel relation to the shaft i8 for engagement of the peripheral faces of the rice rollers against the inside face of the grinding ring. As illustrated, the rollers are six in number but the same may be of any desired number with each roller mounted for rotation on a shaft 23 which is bolted or otherwise aixed at its ends to upper and lower arms 24 and 25 of a yoke 26 with the shafts extending centrally through the roller and with radial bearings 27 and 28 arranged between the shaft and the roller adjacent the top and bottom thereof.

The yokes 26 are mounted in arcuately spaced relation on spiders 29 and 30 which are splined or otherwise secured on the shaft 1S above the bearing support 20 for rotation of the yokes with said shaft. The yokes have inward and outward radial movement with reference to the spiders 29 and 30 on upper and lower cylindrical bars 31 and 32 for each yoke which at their outer ends snugly and slidably fit cylindrical openings 33 and 34 in the upper and lower arms 24 and 25 respectively of the yokes and at their inner ends the said Abars snugly t cylindrical openings 35 and 36 in the upper and lower spiders respectively. A clearance is provided between the inner ends of the arms of the yokes and the outer faces of the spiders to permit of limited radial movement of the yokes for varying the pressure of the grinding rollers 22 against the grinding ring i7.

The yokes are moved outwardly by pressure responsive means consisting of a piston for each yoke having a piston head 3S mounted on the inner end of a piston rod 39 which is arranged with the outer end thereof normally disposed against a web 4i) connecting the upper and lower arms 24 and 25 of each yoke. The pistons are radially disposed and are arranged for radial movement in cylindrical bores 4l respectively formed in a head 42 secured on the shaft f8 in fixed position between the spiders 29 and 30. The head 42 is of hollow formation and constitutes a pressure chamber with the bores emanating in equally spaced arcuate relation on radiuses which extend centrally through the shafts 23 of the grinding rollers 22. For convenience in manufacture, the head 42 may be formed of upper and lower annular plates 44 and 45 which are bolted or otherwise affixed to a ring member 46 forming the outer wall of the head and which plates are also bolted or otherwise atiixed to a central sleeve 47 snugly fitting the central shaft 1S. The outer ends of the bores 41 are closed by plates `48 arranged in recesses in the outer face of the ring member 45 and which are bolted or otherwise secured in position therein with the piston shafts slidably projecting through central openings 49 therein.

The pressure chamber is under the pressure of a fluid such as air or a liquid which is admitted thereto by a pipeline 51 connected with an opening 52 extending into the pressure chamber through the outer wall 46 and with the upper end of the pipeline connected with the lower rotating portion 53 of a slip ring coupling 54. The upper portion 55 of the coupling is secured in fixed position by straps 57 secured to the casing portion iti and has a fluid supply pipe 56 connected with a fluid pressure supply means (not shown). A valve (not shown) is arranged in the fluid supply pipe 56 for regulating the flow of the fluid to the pressure chamber..

The central shaft 1S is rotated by a drive shaft 53 operatively connected therewith by a bevel gear S9 and a pinion 6i) splined or otherwise affixed to the central shaft 18 and drive shaft 53 respectively. The central shaft protrudes downwardly through the base plate i2 with the bevel gear 59 and pinion titl arranged in a gear case 6l which is bolted or otherwise aixed to the underside of the base plate i2 between the supporting bases 13 and i4. The drive shaft S8 is journaled in a bearing 62 mounted in a support 63 which is bolted or otherwise axed to the bottom wall of the gear case 61. The

drive shaft protrudes through a packing gland 64 aliixed to a side wall of the gear case for preventing leakage of lubricating oil from the gear case.

v The material to be ground is fed into a hopper 67 aft'ixed to the mill at one side thereof and is forced into the mill by a rotatably mounted impeller 68 driven by Vany desired means (not shown). A deflector plate 69 is bolted or otherwise afliXed to the upper portion 1t) of the casing for dei'lecting the material downwardly etweeri the grinding ring and rollers.

The comminuted material is drawn olf upwardly through the casing by means of a cyclone collector connected by piping (not shown) with the top of the upper portion thereof. Air for the upward flow of the comminuted material is drawn into the mill by the cy- 'clone collector through a series of radially arranged openings 7()Y in the lower portion 11 of the casing and which openings are provided with grills 71 or other inearis for regulating the quantity of air admitted lthrough the openings. The coarse material falls onto a platform 72 which is bolted or otherwise affixed to the lower portion 11 of the casing and extends inwardly therefrom with the annular inner edge 73 of the platform terminating in narrowly spaced relation from the bearing supportl 20. A series of arms 75 having plow shaped free kends 76 are bolted or otherwise atiixed to the yokes 26 and rotate therewith for throwing thev coarse material upwardly between the grinding rollers 22 for additional grinding action.

With the building up of the operative rotational speed 'of the shaft 18, the yokes will move radially outward on the bars 31 and the rollers 22 will be forced against the grinding ring by the centrifugal force of rotation. With the feeding of the material to be ground, the valve in the pipe line 56 may be opened as desired t0 admit fluid under pressure to the pressure chamber so as yto force the pistons radially outward against the yokes and thus increase the grinding pressure of the rollers against the grinding ring. Coil springs 77 mounted on the piston rods 39 between the piston heads 38 and the plates 48 bias the pistons inwardly. This maintains the 'pistons out of engagement with the yokes until the fluid 'pressure of the pressure responsive means is admitted to 'the pressure chamber, the pressure of which is relatively greater than the springs.

Instead of mounting the rollers for rotation on independent yokes, a yoke may be provided for each pair of rollers as shown in the form of the invention illustrated in FIGS. 4 and 5 of the drawings. In this form of the invention the rollers are relatively larger in diameter than in the previous form and being relatively heavier, the centrifugal force of the rotating rollers about the central shaft will be relatively greater. In the embodiment illustrated, the rollers 80 are four in number, each pair of which is mounted on a yoke 81 for grinding action against a grinding ring 82 similar to the bull ring in the previous form of the invention. Each of the yokes 81 include upper and lower arms 83 and 84 which are connected together by a vertical web 85 located intermediate the ends thereof. The rollers are mounted for turning movement on upright shafts 86 which are journaled in radial bearings 87 and 88 adjacent the ends of the yokes and with the shafts bolted or otherwise affixed at their ends to the upper and lower arms 83 and 84 of the yokes.

The yokes are arranged in oppositely spaced relation and have inward andV outward radial movement with reference to upper and lower cylindrical blocks 89 and '90 which are splined or otherwise aiixed to a rotatably mounted shaft 91 similar to the central shaft 18 in the previous form of the invention. The yokes have turning movement with the shaft and for this purpose upper and lower cylindrical bars 92 and 93 are provided which at their outer kends snugly and slidably tit cylindrical openings'94 and 95 inthe upper and lower arms 83 and 84 of the yokes and at their inner ends said bars snugly fit cylindrical openings 96 and 97 in the cylindrical blocks 89 and 9) respectively. A clearance is provided between the inner ends of the arms 83 and 84 of each of the yokes and the outer periphery of the blocks 89 and 90 so as to permit of limited radial movement of the yokes for varying the pressure of the grinding roller against the grinding ring 82. The yokes are moved outwardly by a pressure responsive means for each yoke as in the previous form of the invention, and which in this form consists of a piston having a piston head 98 mounted on the inner end of a piston rod 99 with the outer end of the rods disposed against the web of one of the yokes. The pistons are radially disposed and are arranged for radial movement in cylindrical bores 161) respectively formed in a head 101 secured on the shaft 91 in fixed position between the blocks 89 and 98. The head 161 is of hollow formation and constitutes a pressure chamber with the bores 1li() emanating therefrom in diametrical relation. The head 161 may be formed of upper and lower plates 102 and 103 which are bolted or otherwise aiiixed to a central member 104 having the bores 1% and which plates are also bolted or otherwise affixed to a central sleeve 105 which snugly lits the central shaft 91. The outer ends of the bores 100 are closed by plates 1116 which'are arranged in recesses in the outer face of the central member 104 and are bolted or otherwise secured in position therein with the piston rods 99 slidably projecting through central openings 107 therein.

The grinding ring 82 is supported on an annular ledge 109 formed in the lower portion 110 of a casing similar to the casing in the previous form of the invention. The

upper portion 111 thereof is similarly connected with a cyclone collector for drawing off the comminuted material upwardly through the casing. The casing portion also includes radially arranged openings (not shown) similar to the openings 70 in the previous form and through which air enters the casing for the upflow of the comminuted material. The shaft 91 is Connected with a drive shaft (not shown) similar to the drive shaft 58 for effecting rotation of the yokes 92 and rollers 80 therewith. Fluid under pressure is admitted to the pressure chamber within the head 101 for movement of the pistons outwardly in the bores 1118 to thereby increase the pressure of the rollers 8d against the grinding ring 82 with the rotation thereof. The fluid such as air or liquid is admitted to the pressure chamber through a pipeline 112 which is connected with a slip ring coupling similar to the slip ring coupling 54 in the previous form of the invention. In this form also arms 112 are affixed to the yokes 85 and have plow shaped outer ends similar to the arms 75 in the previous form of the invention for throwing the coarse material upwardly between the grinding rollers 80 for additional grinding action.

This construction permits of the use of relatively large and heavy rollers 80 which will have considerable pressure against the bull ring due to the centrifugal force of rotation thereof with the rotation of the shaft 92. This pressure may be increased as desired by the opening up of the pipeline 112 to admit liuid under pressure against the pressure responsive means for forcing the rollers outwardly against the bull ring by the pressure of the fluid.

While the preferred forms of the invention have been shown and described herein, it is to be understood that the same is not so limited but shall cover and include any and all modifications of the invention which fall within the purview thereof.

What is claimed is:

l. In a mill for comminuting solid material a casing supported in upright relation, a cylindrical grinding ring,r supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journaled for rotation centrally within said casing, a plurality of arcuately spaced yokes on each of which at least one of said rollers is rotatably mounted on an upwardly extending axis to dispose the peripheral faces of said rollers in engagement with, the inner peripheral face of said grinding ring, upper and lower members affixed to said shaft, radially arranged bars connecting said upper and lower members with said yokes for radial sliding movement of said yokes imparted thereto by centrifugal force with the rotation thereof with said driven shaft whereby said centrifugal force forces said rollers against said grinding rings, a hollow member carried by said shaft providing a lluid pressure chamber and having radially arranged bores, pistons mounted in said bores with the outer ends thereof protruding through said hollow member and engaging said yokes respectively, and conduit means connected with a source of fluid under pressure 'and opening into said fluid pressure chamber for admitting fluid under pressure thereto to move said pistons outwardly against said yokes to thereby increase the grinding pressure of the rollers against said grinding ring by the pressure of said iluid.

2. In a mill for comminuting solid material a casing supported in upright relation, a cylindrical grinding ring supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journalled for rotation centrally within said casing, a plurality of arcuately spaced yokes on each of which at least one of said rollers is rotatably mounted on an upwardly extending axis to dispose said rollers in grinding engagement with the inner peripheral face of said grinding ring, upper and lower members affixed to said shaft, radially arranged bars connecting said upper and lower members with said yokes for radial sliding movement of said yolies, a hollow member carried by said shaft providing a fluid pressure chamber and having radially 'arranged bores, pistons mounted in said bores with the outer ends thereof protruding through said hollow member and engaging said yokes respectively, and conduit means connected with a source of fluid under pressure and opening into said fluid pressure chamber for admitting iluid under pressure thereto to move said pistons outwardly against said yokes to thereby force said rollers against said grinding ring by the pressure of said uid.

3. In a mill for comminuting solid material a casing supported in upright relation, a cylindrical grinding ring supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journalled for rotation centrally within said casing, a plurality of arcuately spaced yokes on each of which at least one of said rollers is rotatably mounted on an upwardly extending axis to dispose said rollers in grinding engagement with the inner peripheral face of said grinding ring, means carried by said shaft supporting said yokes for radial movement, a hollow member carried by said shaft providing a iluid pressure chamber and having radially arranged bores, displaceable means mounted in said bores with said means protruding through said hollow member and engaging said yokes respectively, and conduit means connected with 'a source of fluid under pressure and opening into said fluid pressure chamber for admitting fluid under pressure thereto to move said displaceable means outwardly against said yokes to thereby force said rollers against said grinding ring by the pressure of said iluid.

4. In a mill for comminuting solid material a casing supported in upright relation, a cylindrical grinding ring supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journalled for rotation centrally within said casing, yokes on which said rollers are rotably mounted on upright axes to dispose said rollers in engagement with the inner peripheral face of said grinding ring, means carried by said shaft supporting said yokes for radial movement, uid pressure responsive means including a hollow member carried by said shaft providing a fluid pressure chamber and having radially arranged bores, displaceable means mounted in said bores and protruding through said follow member into engagement with said yolres respectively, and conduit means connected with a source of fluid under pressure and opening into said fluid pressure chamber for admitting iluid under pressure thereto to move said displaceable means outwardly `against said yokes to thereby force said rollers against said grinding ring by the pressure of said fluid.

5. In a mill for comminuting solid material a casing supported in upright relation, a cylindrical grinding ring supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journalled for rotation centrally within said casing, a plurality of arcuately spaced yokes having upwardly extending shafts adjacent the ends thereof rotatably mounting two of said rollers on each yoke to dispose the peripheral faces of said rollers in rolling engagement with the inner peripheral face of said grinding ring, upper and lower members aixed to said shaft, radially arranged bars connecting said upper and lower members with said yokes for radial sliding movement of said yokes imparted thereto by centrifugal force with the rotation thereof with said driven shaft whereby said centrifugal force forces said rollers against said grinding ring, a hollow member carried by said shaft providing a fluid pressure chamber and having radially arranged bores, pistons mounted in said bores with the outer ends thereof protruding through said hollow member and engaging said yolres respectively, and conduit means connected with a source of fluid under pressure and opening into said uid pressure chamber for admitting fluid under pressure thereto to move said pistons outwardly against said yokes to ythereby increase the grinding pressure of the rollers against said grinding ring by the pressure of said fluid.

6. In a mill for comminuting solid material a casing supported in upright relation, a cylindrical grinding ring supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journalled for rotation centrally within said casing, a plurality of arcuately spaced yokes on each of which at least one of said rollers is rotatably mounted on an upwardly extending axis to dispose the peripheral faces of said rollers in engagement with the inner peripheral face of said grinding ring, upper and lower members affixed to said shaft, and radially arranged bars connecting said upper and lower members with said yokes for radial sliding movement of said yokes imparted thereto by centrifugal force with the rotation thereof with said driven shaft whereby said centrifugal force forces said rollers against said grinding ring.

7. In a .mill or comminuting solid material a casing supported in upright relation, a cylindrical grinding ring supported by said casing and having a peripheral inner grinding face, a plurality of arcuately spaced grinding rollers, a driven shaft journalled for rotation centrally within said casing, a plurality of arcuately spaced yokes having upwardly extending shafts adjacent the ends thereof rotatably mounting two of said rollers on each yoke to dispose the peripheral faces of said rollers in rolling engagement with the inner peripheral face of said grinding ring, upper and lower members axed to said shaft, and radially arranged bars connecting said upper and lower members with said yokes for radial sliding movement :of said yokes imparted thereto by centrifugal force with the rotation thereof vwith said driven shaft whereby said centrifugal force forces said rollers against said grinding ring.

References Cited in the le of this patent UNITED STATES PATENTS 

